A network, sometimes referred to as a graph or circuit, is constituted by a number of nodes and a number of lines each connecting one node to another node. In network terminology, a node is usually referred to as a vertex, the line connecting this node to another node is referred to as a route or edge, the number of routes connecting to a node is referred to as the degree of this node, and the distribution of these degrees is referred to as a degree distribution.
The term network topology defines the organization of the points and the connections between points to form a network, whereas it can sometimes be referred to as the resulting network itself or a subset of the resulting network. For instance, the term ‘ring network’ can be mutually understandable as ‘ring topology’. In a computer network, each node may be a network switch in a network on chip, a core of a processor, a processor on a motherboard, a computer, a network switch in a cluster computer, a server in any infrastructure, or an information center.
In the case of a supercomputer, the efficiency of transmission of message packets between points is affected by the network infrastructure. In practice, the delay of transmission of message packets is usually caused by the time of a network switch buffering a message packet, by the time of delay while trying to acquire a channel, or by the time of redirection. In a network topology system, if on average, a message packet needs to visit many network switches, the transmission or waiting time required by this message packet will become very long, leading to a heavy burden on each node.
As described above, if a network topology is not subjected to an optimization process, a message packet may be transmitted through an inferior route, so that in addition to the increase of the load on each network switch, the transmission time also becomes longer.